Solar Cell Selective Emitter via Laser Doping
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Solution Overview
Problem
The manufacturing process of solar cells with selective dopant layers is complex and low in productivity due to the need for multiple doping processes and precise mask alignment, which hinders the enhancement of dopant layer properties and electrode alignment.
Innovation Solution
A solar cell design featuring a semiconductor substrate with a selective emitter layer and passivation layers, where the first portion has a higher dopant concentration and lower resistance, and the second portion has a uniform dopant distribution, allowing for enhanced alignment and efficiency through localized heating and doping, simplifying the manufacturing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a selective dopant layer is formed using multiple doping processes and masks, then the dopant layer properties are enhanced, but the manufacturing process becomes complex and productivity decreases
Solution Approach 1:
The dopant layer is segmented into multiple regions with different doping concentrations (first dopant region with first concentration, second dopant region with second concentration). This segmentation is achieved by forming the dopant layer in a single process and then selectively removing portions, eliminating the need for multiple doping processes and masks while maintaining the selective structure properties
Solution Approach 2:
Instead of forming different dopant regions through multiple doping processes (conventional approach), the invention inverts the approach by forming a uniform dopant layer first and then selectively removing portions to create the desired concentration profile. This reverse methodology simplifies the manufacturing process while achieving the same functional result
2Manufacturing precision
If multiple doping processes are used to form selective dopant layers, then the dopant concentration distribution is improved, but the alignment between dopant layer and electrode deteriorates
Solution Approach 1:
The formation of the selective dopant layer structure and the electrode positioning are merged into a single manufacturing step. The electrode is formed simultaneously with the selective removal of the dopant layer, ensuring perfect alignment between the electrode and the dopant regions without requiring separate alignment processes
Solution Approach 2:
The single dopant layer structure serves multiple functions: it provides the selective concentration distribution for device performance and simultaneously defines the alignment reference for electrode placement. The structure self-aligns the electrode position through its inherent geometric configuration, eliminating the need for complex alignment procedures
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach improves the alignment and efficiency of the dopant layer and electrode, reducing manufacturing complexity and costs while maintaining high solar cell performance by using localized heating to diffuse dopants and forming a selective emitter structure.
Implementation Method 1
The first dopant of the heated portion of the passivation layer is diffused into an inside of the semiconductor substrate by the locally heating
Data Source
AI summary
A method for manufacturing a solar cell according to an embodiment of the invention includes forming an emitter layer having an emitter dopant of a second conductive type opposite to a first conductive type on a first surface on a semiconductor substrate; forming a passivation layer including a first dopant of the first conductive type on a second surface of the semiconductor substrate; forming a back surface field layer including a first portion on the second surface by locally heating a portion of the passivation layer using a laser; and forming an electrode electrically connected to the first portion of the back surface field layer through an opening of the passivation layer after the first portion of the back surface field layer is formed on the second surface, wherein the back surface field layer is locally formed between the electrode and the second surface.